NAME
DATE
CLASS
Chapter 12
Use with Section 2
REINFORCEMENT
Relative Ages of Rocks
In the blank at the left, write the term that completes each statement.
1. Natural laws govern the way geologists determine the age of rock
deposits. This technique is called
.
2. The principle of
states that an older rock layer and things buried
in it occur beneath younger layers unless the layers have been
disturbed.
3. Forces generated by
may overturn rock layers.
4. Some rock layers are incomplete. The gaps are called
5. A common cause of gaps in rock layers is
.
.
Look at the cross-sectional view of the rock layers shown in the diagram below. For each question, decide which of the
two named materials is older. Assume the layers have not been overturned. Write the name of the older material on the
line provided.
6. tan sandstone and
brown sandstone
7. brown sandstone
and gray limestone
8. gabbro dike and
brown sandstone
Red sandstone
9. gabbro dike and
gray shale
10. snail fossil and
trilobite fossil
Dinosaur bone
Tan limestone
Gray limestone
Tan sandstone
11. snail fossil and
dinosaur bone
Brown
sandstone
12. snail fossil and
green shale
14. red sandstone and
gray limestone
Snail fossil
Green shale
Gabbro d
ike
13. dinosaur bone and
red sandstone
Brown
sandstone
Black shale
Gray shale
Trilobite fossil
15. tan limestone and
tan sandstone
16. tan limestone and
gray limestone
Complete the following statement.
17. The type of unconformity shown in the diagram is a(n)
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